Adhesive bonding of backseams

ABSTRACT

In forming a backseam for a shoe upper two quarters are assembled on two surfaces of a forming member which meet at a curved edge corresponding to the shape of the backseam, and the edges of the quarters are bonded together, the edges of the quarters being arranged to abut at the edge of the forming member, or the edge of the first quarter being bent around the edge of the forming member on to the second surface and overlapped by the edge of the second quarter.  Leather quarters are bonded by adhesive, but weldable plastic coated fabric quarters are bonded by welding.  The forming member may have parallel surfaces with a rounded edge (Figs. 4, 5, Figs. not shown), one surface chamfered (Figs. 2, 3), or both surfaces chamfered (Figs. 6-9).  Alternatively the member bay comprise curved, preferably cylindrical, surfaces 124, 126 (fig. 10) meeting at a curved edge 128 at approximately 90 degrees.  The seam shown in Fig. 3 is formed by folding the first leather quarter 8 around the edge of member 12, sticking it thereto by pressure-sensitive adhesive, scouring the edge portion 22 until it is level with the second surface 20, coating with adhesive the skived face 6 of the second quarter and arranging it over surface 22, and bonding the parts together by heat and slight pressure using a dielectric heating apparatus.  In Figs. 4 and 5 the quarters are of cloth coated with polyvinyl chloride and are arranged with the cloth innermost.  The coating 46 of quarter 40 is skived at 52 and overlapped by the edge of quarter 32.  Metal template 48 with the quarters is lightly pressed between bed 58 and block 60 of silicone rubber and a high frequency electric field established by electrode 64.  In Figs. 6-9 quarters comprising layers of leather 76, 84, polystyrene impregnated fabric 78, 86, to form a counter stiffener, and lining leather 80, 88 are skived at 83, 96, and 112, the latter surface is coated with adhesive and covered by the skived surface 98 of layer 84 and the parts joined by high frequency heating.  The seams shown in Figs. 11-18 are formed on former 122 (Fig. 10). The quarters comprise fabric 130, 132 coated with polyvinyl chloride (Figs. 11, 13, 14), polystyrene impregnated fabric (Fig. 12), leather (Figs. 15, 16), or layers of leather 191, heat mouldable stiffener 192, and lining 193 (Figs. 17, 18).  The seams are formed by skiving one surface of the first quarter (Fig. 11) or on the surface of both quarters (Figs. 15, 16, 18), by skiving two surfaces of the first quarter which engage between two reentrant skived faces of the second quarter (Fig. 17), or by butting the quarters (Figs. 13, 14).  The adhesive may be heat or solvent activated.  A heel stiffening blank 140, 160 may be incorporated in the seam (Figs. 12, 14).

y 7 R. HANSON 3,317,941

ADHESIVE BONDING OF BACKSEAMS Filed Sept. 17, 1964 Inventor Ray/n and Hanson By his After-neg United States Patent 3,317,941 ADHESIVE BGNDING 0F BACKSEAMS Raymond Hanson, Leicester, England, assiguor to United Shoe Machinery (Iorporation, Flemington, N.J., a corporation of New Jersey Filed Sept. 17, 1964, Ser. No. 397,213 Claims priority, application Great Britain, Nov. 27, 1963, 46,781/63 4 Claims. (Cl. 12146) This invention relates to the adhesive joinder of shoe parts and, more particularly, to a method of forming an adhesively bonded backseam.

In the most commonly employed method of forming shoe uppers, the uppers are assembled by stitching together a plurality of appropriately shaped components. The seam located at the back or heel portion of the shoe, commonly referred to as the back seam, is normally formed with the partially formed upper turned inside out by alining the ends of the quarter components in face to face relationship and applying a stitched seam thereto. The stitching is completed with the upper turned inside out so that when the upper is reversed, the alined ends to which the stitching is applied will be directed inwardly and thereby concealed in the finished shoe. If the quarter ends were initially folded inwardly into alined face to face relation with the upper in its normal orientation, the alined ends could not be introduced to a stitching machine Without turning the partially formed upper inside out. It is to be noted that the formation of all the stitched seams of the upper, with the exception of the backseam, are accomplished with the upper in the fiat. When the quarter ends are positioned in alined face to face relation, the upper becomes threedimensional. When the stitched seam is completed, the upper is reversed whereby the stitched backseam is on the inside of the upper.

The surplus material at the backse-am is removed after completion of the stitching operation, i.e., the portions of the quarter ends not exposed to the stitching are removed or flattened. The stitched seam itself is rubbed in order to provide as flat or smooth a surface as'possible. This operation is necessary because of the position of the stitched seam on the inside of the finished shoe. Failure to provide a smooth surface results in extreme discomfort to a wearer.

The backseam of a shoe upper is subjected to high strain during the lasting operations and, also, during normal use of the finished shoe. Accordingly, normal shoemaking practice requires the reinforcement of the backseam after the completion of the above described manufacturing procedure, commonly by the application of tape adhesively secured along the stitching.

The plurality of diflicult operations delineated above made the formation of backseams a time consuming and costly part of the sh-oemaking process. Further, failure to take extreme care in the completion of these operations invariably resulted in a shoe which was extremely uncomfortable for the wearer. The inexact, cumbersome nature of the method made it impossible to consider automation of the procedure.

Accordingly, it is an object of this invention to provide an improved method of forming shoe seams.

It is a further and more specific object of this invention to provide a method of forming adhesively bonded backseams which is simpler than the procedure presently followed to form stitched backseams.

It is a still further object of this invention to provide a method of forming adheively bonded backseams which are of sufiicient strength to Withstand lasting and wearing strains without being reinforced by supplemental ice means, It is also an object to provide a method which produces a smooth backseam without rubbing operations.

To these ends there is provided a method of forming an adhesively bonded backseam comprising skiving a curved edge portion of a first shoe quarter to provide an angularly skived face extending about said curved edge portion, providing an elongated template comprising a wrap surface having an angular end face and a generally longitudinal face, a guide surface, and a curved edge corresponding in shape to the curved edge portion of said first quarter formed at the intersection of the angular end face and longitudinal face, positioning a second shoe quarter against the longitudinal face of the wrap surface with a curved edge portion of said second quarter extending beyond the curved edge of the template, coating the angular end face of the wrap surface and/or the curved edge portion of said second quarter with adhesive, folding the curved edge portion of the second quarter over the curved edge of the template whereby the curved edge portion of the second quarter is positioned in abutting relation to the angular end face and is bonded thereto by said coating of adhesive, removing that portion of the curved edge portion of the second quarter extending above the guide surface of the template thereby to provide a skived face on said second quarter which forms a continuous flat surface in combination with said guide surface, coating the skived face of the first quarter and/ or the skived face of the second quarter with adhesive, and positioning the first quarter against the guide surface of the template with the skived face of the first quarter in alined engagement with the skived face of the second quarter.

The above and other features of this invention will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the method embodying the invention can be used for making backseams regardless of the kind of upper material to be employed. The principles and features of this invention may be utilized in varied and numerous embodiments and applications without departing from the scope of the invention.

In the drawings:

FIG. 1 illustrates two shoe quarters of appropriate shape for use in the method embodying the invention;

FIG. 2 shows the shoe quarter 2 of FIG. 1 positioned against a template; and

FIG. 3 illustrates an adhesively bonded backseam formed by the method embodying the invention.

In practicing the method of this invention, a first quarter 2 is cut to the appropriate configuration shown in FIG. 1. The quarter 2 is skived on the inner flesh surface along a curved edge portion 4 to provide an angularly skived face 6. In the preferred embodiment, the width of the angularly skived portion 6 is or greater.

A second quarter 8 is cut to a shape corresponding to that of the first quarter 2 but slightly greater in length. As illustrated in FIG. 1, the second quarter 8 is larger than the first quarter 2 by an amount equal to that portion extending beyond the line denoted by the reference character 10, said amount hereinafter being referred to as the overage 11. In the preferred embodiment, the overage 11 is or greater in width.

The second quarter 8 is positioned against a template 12 which is substantially the same thickness as the leather quarters 2 and 8. The template 12 comprises a wrap surface 13 having an angular or chamfered end face 14 and a generally longitudinal face 16, a guide surface 18, and a curved edge 20 corresponding in shape to the curved edge portion of the first quarter 2 formed at the intersection of the angular end face 14 and the longitudinal face 16. The quarter 8 is positioned against the template 12 with the inner flesh side thereof in engagement with the .3 longitudinal face 16 of the template 12 and with the overage 11 extending beyond the curved edge Ztl.

The cha-mfered or angular end face 14 and/or the flesh side of the overage 11 is thereafter coated with a layer of pressure sensitive adhesive and the overage 11 folded over onto the angular end face 14. The location of the overage 11 after the folding ope-ration is illustrated in dotted lines in FIG. 2. The outer surface of the ove-rage 11 is firmly pressed against the angular end face 14- thereby to establish a bond therebetween by means of the pressure sensitive adhesive. The folding operation may be performed on a folding machine of any convenient type.

The template 12 wit-h the quarter 8 bonded thereto is then presented to a scouring wheel and that portion of the overage 11 extending above the guide surface 18 of the template 12 removed. The face 18 of the template is conveniently used as a guide surface to aid in positioning the scouring tool. The resulting skived face forms a continuous fiat surface in combination with the guide surface 18 of the template 12.

The skived face 6 of the quarter 2 and/or the skived face 22 of the quarter 8 is then provided with a coating of adhesive, preferably of the hot-melt type in accordance with the requirements of the preferred embodiment of the invention described hereinafter. The first quarter 2 is thereafter positioned against the guide surface 18 with the skived face 6 in alined engagement with the skived face 22.

In the preferred embodiment, the hot-melt adhesive is activated dielectrically by positioning the seam formed by the skived faces 6 and 22 between the electrodes of a dielectric heating apparatus. When the activation of the adhesive has been completed, the quarters 2 and 3 are stripped from the template 12 and the pressure sensitive adhesive removed. In the alternative, pressure sensitive adhesive positioned on the overage 11 may be used to assist in securing a counter in position.

The resultant backseam is of a strength equal to or greater than the normal stitched seam as the adhered faces 6 and 22 are skived and positioned in such a manner as to provide a maximum surface area for bonding. That is, the method described above provides considerably elongated abutting surfaces (6 and 22) which can be adhesively joined thereby to provide a strong backseam. Further, in contrast to the normal stitched backsearn which is primarily subjected to peeling forces, the method of forming the backseam disclosed above provides a backseam which is of such orientation as to be exposed principally to direct tension during lasting and wear. Thus, the danger of rupture, is diminished as the seams resistance to tension is greater than to peeling. The above defined method also eliminates the need for rubbing operations as the backseam formed thereby initially provides as smooth surface.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A method of forming an adhesively bonded backseam in shoe uppers comprising skiving a curved edge portion of a first shoe quarter to provide an angularly skived face defining said curved edge portion, providing an elongated template having wrap surfaces comprising an angular end face and a generally longitudinal face, a guide surface, and a curved edge corresponding in shape to the curved edge portion of said first quarter formed at the intersection of the angular end face and the longitudinal face, positioning a second shoe quarter against the longitudinal face of the wrap surface with a curved edge portion of said second shoe quarter extending beyond the curved edge of the template, coating at least one of the members comprising the angular end face of the wrap surface and the curved edge portion of the second quarter with adhesive, folding the curved edge portion of the second quarter over said curved edge of the template whereby the curved edge portion of the shoe quarter is positioned in abutting relation to the angular end face and is bonded thereto by said coating of adhesive, removing that portion of the curved edge portion of the second quarter extending above the guide surface of the template thereby to provide a skived face on said second quarter which forms a continuous flat surface in combination with said guide surface, coating at least one of the skived faces of the shoe quarters with adhesive, and positioning the first quarter against the guide surface of the template with the skived face of the first quarter in alined abutting relation with the skived surface of the second quarter.

2. A method of forming an adhesively bonded backseam in shoe uppers comprising skiving a curved edge portion of a first shoe quarter to provide an angularly skived face defining about said curved edge portion, pro viding an elongated template having wrap surfaces comprising an angular end face and a generally longitudinal face, a guide surface, and a curved edge corresponding in shape to the curved edge portion of said first quarter formed at the intersection of the angular end face and the longitudinal face, positioning a second shoe quarter against the longitudinal face of the Wrap surface with a curved edge portion of said second shoe quarter extending beyond the curved edge of the template, coating at least one of the members comprising the angular end face of the wrap surface and the curved edge portion of the second quarter with adhesive, folding the curved edge portion of the second quarter over said curved edge of the template whereby the curved edge portion of the second shoe quarter is positioned in abutting relation to the angular end face and is bonded thereto by said coating of adhesive, removing that portion of the curved edge portion of the second quarter extending above the guide surface of the template to provide a skived face on said second quarter, coating at least one of the skived faces of the shoe quarters with hot melt adhesive, positioning the first quarter against the guide surface of the template with the skived face of the first quarter in alined abutting relation with the skived face of the second quarter, dielectrically activating the hot melt adhesive and removing the bonded quarters from the template.

3. A method of forming an adhesively bonded backseam in shoe uppers comprising skiving the flesh surface of a curved edge portion of a first leather shoe quarter to provide an angularly skived face defining said curved edge portion, providing an elongated template having wrap surfaces comprising an angular end face and a generally longitudinal face, a guide surface, and a curved edge corresponding in shape to the curved edge portion of said first quarter formed at the intersection of the angular end face and the longitudinal face, positioning the flesh surface of a second shoe quarter against the longitudinal face of the wrap surface with a curved edge portion of said second shoe quarter extending beyond the curved edge of the template, coating at least one of the members comprising the angular end face of the Wrap surface and the curved edge portion of the second quarter with pressure sensitive adhesive, folding the curved edge portion of the second quarter over said curved edge of the template whereby the curved edge portion of the second shoe quarter is positioned in abutting relation to the angular end face, pressing the curved edge portion of the second shoe quarter against the end face of the template whereby the curved edge portion is bonded thereto by said coating of pressure sensitive adhesive, removing that portion of the curved edge portion of the second quarter extending above the guide surface of the template thereby to provide a skived face on said second quarter, coating at least one of the skived faces of the leather quarters with adhesive, and positioning the first quarter against the guide surface of the template with the skived face of the first quarter in alined abutting relation with the skived surface of the second quarter.

'4. A method of forming an adhesively bonded backseam in shoe uppers comprising skiving the flesh surface of a curved edge portion of a first leather shoe quarter to provide an angularly skived face extending about said curved edge portion, providing an elongated template having Wrap surfaces comprising an angular end face and a generally longitudinal face, a guide surface, and a curved edge corresponding in shape to the curved edge portion of said first quarter formed at the intersection of the angular end face and the longitudinal face, positioning the flesh surface of a second shoe quarter against the longitudinal face of the wrap surface With a curved edge portion of said second shoe quarter extending beyond the curved edge of the template, coating at least one of the members comprising the angular end face of the wrap surface and the curved edge portion of the second quar ter with pressure-sensitive adhesive, folding the curved edge portion of the second quarter over said curved edge of the template whereby the curved edge portion of the second quarter is positioned in abutting relation to the angular end face, pressing the curved edge portion of the second quarter against the end face of the template whereby the curved edge portion is bonded thereto by said coating of pressure-sensitive adhesive, removing that portion of the curved edge portion of the second quarter extending above the guide surface of the template to provide a skived face on said second quarter which forms a continuous flat surface in combination with said guide surface, coating at least one of the skived faces of the leather quarters with hot melt adhesive, positioning the first quarter against the guide surface of the template with the skived face of the first quarter in alined abutting relation with the skived face of the second quarter, dielectrically activating the hot melt adhesive by positioning the abutting skived surfaces between the electrodes of the dielectric heating apparatus, and removing the bonded quarters from the template. 1

References Cited by the Examiner UNITED STATES PATENTS 352,404- 11/ 1886 Fitzgerald 6921.5 1,814,518 7/1931 McGrail 12-1'46 X 2,666,935 1/1954 Gilbert et a1. 12-146 X JORDAN FRANKLIN, Primary Examiner.

H. H. HUNTER, Assistant Examiner. 

1. A METHOD OF FORMING AN ADHESIVELY BONDED BACKSEAM IN SHOE UPPERS COMPRISING SKIVING A CURVED EDGE PORTION OF A FIRST SHOE QUARTR TO PROVIDE AN ANGULARLY SKIVED FACE DEFINING SAID CURVED EDGE PORTION, PROVIDING AN ELONGATED TEMPALTE HAVING WRAP SURFACES COMPRISING AN ANGULAR END FACE AND A GENERALLY LONGITUDINAL FACE, A GUIDE SURFACE, AND A CURVED EDGE CORRESPONDING IN SHAPE TO THE CURVED EDGE PORTION OF SAID FIRST QUARTER FORMED AT THE INTERSECTION OF THE ANGULAR END FACE AND THE LONGITUDINAL FACE, POSITIONING A SECOND SHOE QUARTR AGAINST THE LONGITUDINAL FACE OF THE WRAP SURFACE WITH A CURVED EDGE PORTION OF SAID SECOND SHOE QUARTE EXTENDING BEYOND THE CURVED EDGE OF THE TEMPLATE, COATING AT LEAST ONE OF THE MEMBERS COMPRISING THE ANGULAR END FACE OF THE WRAP SURFACE AND THE CURVED EDGE PORTION OF THE SECOND QUARTER WITH ADHESIVE, FOLDING THE CURVED EDGE PORTION OF THE SECOND QUARTER OVER SID CORVED EDGE OF THE TEMPLATE WHEREBY THE CURVED EDGE PORTION OF THE SHOE QUARTER IS POSITIONED IN BUTTING RELATION TO THE ANGULAR END FACE AND IS BONDED THERETO BY SAID COATING OF ADHESIVE, REMOVING THE PORTION OF THE CURVED EDGE PORTION OF THE SECOND QUARTER EXTENDING ABOVE THE GUIDE SURFACE OF THE TEMPALTE THEREBY TO PROVIDE A SKIVED FACE ON SAID SECOND QUARTER WHICH FORMS A CONTINUOUS FLAT SURFACE IN COMBINATION WITH SAID GUIDE SURFACE, COATING AT LEAST ONE OF THE SKIVED FACES OF THE SHOE QUARTERS WITH ADHESIVE, AND POSITIONING THE FIRST QUARTER AGAINST THE GUIDE SURFACE OF THE TEMPLATE WITH THE SKIVED FACE OF THE FIRST QUARTER IN ALINED ABUTING RELATION WITHTHE SKIVED SURFACE OF THE SECOND QUARTER. 